The present invention relates to a battery cell assembly system which automatically packages battery plates in separator material and assembles the packaged plates in a battery cell.
Battery plates for batteries of the lead-acid type are conventionally manufactured by casting a grid structure in a mold. The grid usually comprises a rectangular frame formed with openings, and a laterally projecting conductive lug on its periphery by means of which a plurality of grids of similar polarity may be fused together or otherwise electrically connected in parallel as by a bar leading to a battery post. The grid is coated with an active material paste of lead oxide containing some sulphuric acid, whereafter it is heated to dry and somewhat solidify the paste. The resulting structures, called battery plates, are then subjected to an electrical charge while in sulphuric acid, whereby one group of plates called the negative plates have their lead oxide converted to lead, and another group of plates called the positive plates have their lead oxide converted to lead dioxide.
To prevent shedding of the active material coating from the battery plates when the same are used in a battery, each plate is wrapped or encased in a separator material which ideally on the one hand securely retains the coating on the plate while on the other hand allows unimpeded electrochemical action of the plate when formed with one or more additional plates into a battery. Conventionally, each plate is wrapped in a separator material which is usually of fiberglass. To this end, a fiberglass mat is folded around the plate, and to hold the mat in position on and against the plate a plastic "foot" or sheet of material is folded around the bottom of the plate and mat, and an overlay sheet of perforated plastic is folded around the mat and foot lengthwise of the plate. Ends of the outer sheets of plastic material are then overlapped and joined, for example by heat sealing, to complete the assembly. The wrapping process is usually a manual operation inasmuch as the prior art does not contemplate any generally satisfactory means for automatically wrapping fiberglass around battery plates, and is quite undesirable since fiberglass is a relatively hazardous material to handle and work with.
A series of wrapped or packaged negative and positive plates are then interleaved to alternate negative and positive plates, whereupon the same may be placed in a container to form a battery cell. The cell may comprise any number of plates, with the positive plates being connected in parallel and the negative plates being connected in parallel, so that the entire cell has the desired average rating. A requisite number of cells may then be inserted into an outer housing of a battery, the cells connected in series, a cover installed on the housing and electrolyte introduced therein to complete the battery.
Manifestly, battery plate assemblies and the resulting batteries of the type described are difficult, time consuming and tedious to construct. It would therefore be very desirable to provide some means for automatically manufacturing battery cells, which cells may then be combined to form a battery.